This invention relates generally to surgical instruments and more particularly to instruments such as snares that may be used for grasping and removing material during surgery.
During surgery, there is often a need for the collection and removal of tissue specimens such as polyps or other material from a body cavity of the patient. The removal of such tissue is often accomplished through the use of a snare device or slip-knotted suture loop that is inserted into the patient through a cannula. The snare device is generally mounted to the end of a cable slidably disposed within a flexible tube. The user of the snare device must maneuver the end of the flexible tube and cable through the body cavity, which may have a number of convolutions such as in the case of an intestinal cavity. The snare must then be maneuvered so as to surround the material to be grasped and then cinched around the material, typically using an external actuation mechanism.
The maneuverability of the snare device is generally limited to motion resulting from extension or retraction of the snare from the end of the flexible tube, extension or retraction of the flexible tube and the cable/rod and, under certain circumstances, rotation of the flexible tube and the cable/rod. This limited maneuverability can make it difficult to position the snare around the material of interest, particularly in areas where there is little room for repositioning of the tube and/or cannula.
There is accordingly a need for a surgical instrument snare with an additional manipulation capability that facilitates the maneuvering of the snare to encircle material within a body cavity of a patient.
Accordingly, an embodiment of the present invention provides a surgical instrument for facilitating the capture of objects during surgery. The surgical instrument comprises a flexible tube having a proximal tube end and a distal tube end, the flexible tube defining a cable passageway and being configured for insertion of at least a distal portion of the flexible tube into a body cavity of a patient. The surgical instrument further comprises a flexible cable having a proximal cable end and a distal cable end. At least a portion of the flexible cable is slidably disposed in the cable passageway. A snare loop having a loop member is attached to the distal cable end. The snare loop and the cable are adapted so that the snare loop can be selectively retracted within the cable passageway by sliding the flexible cable proximally within the cable passageway. The snare loop and the cable are also adapted so that at least a portion of the snare loop can be selectively extended from the distal tube end by sliding the flexible cable distally within the cable passageway. The loop member is adapted for selectively encircling and engaging at least a portion of an object in the body cavity. The system also comprises a steering tether having a proximal tether end and a distal tether end. The distal tether end is attached to the loop member so that application of a tensile force to the proximal tether end causes the snare loop to deform in a predetermined manner, thereby facilitating a maneuvering of the snare loop.
Another aspect of the invention provides a surgical instrument for facilitating the capture of objects during surgery. The surgical instrument comprises a snare control module having a body with a distal body end and a proximal body end. The snare control module also has a control slide with a passage formed therein for slidable disposition of at least a portion of the body therethrough. The surgical instrument further comprises a flexible tube having a proximal tube end attached to the distal end of the body and a distal tube end. The flexible tube defines a cable passageway and is configured for insertion of at least a distal portion of the flexible tube into a body cavity of a patient. The surgical instrument still further comprises a flexible cable having a proximal cable end and a distal cable end. At least a portion of the flexible cable is slidably disposed in the cable passageway. The proximal cable end is connected to the control slide so that movement of the control slide toward the proximal body end causes proximal movement of the flexible cable within the cable passageway and movement of the control slide toward the distal body end causes distal movement of the flexible cable within the cable passageway. The instrument also comprises a snare loop having a loop member attached to the distal cable end. The snare loop and the cable are adapted so that the snare loop can be selectively retracted within the cable passageway by sliding the flexible cable proximally within the cable passageway and so that at least a portion of the snare loop can be selectively extended from the distal tube end by sliding the flexible cable distally within the cable passageway. The loop member is adapted for selectively encircling and engaging at least a portion of an object in the body cavity. The surgical instrument further comprises at least one steering tether having a proximal tether end and a distal tether end. The distal tether end of each of the at least one steering tether is attached to the loop member so that application of a tensile force to the proximal tether end causes the snare loop to deform in a predetermined manner, thereby facilitating a maneuvering of the snare loop.
Yet another aspect of the invention provides a method of securing an object disposed within a body cavity of a patient using a surgical instrument of the invention. The surgical instrument has a flexible tube having distal and proximal tube ends and defining a cable passageway, a flexible cable having proximal and distal cable ends and being slidably disposed in the cable passageway, a snare loop attached to the distal cable end, the snare loop and the cable being adapted so that the snare loop can be selectively retracted within the cable passageway by sliding the flexible cable proximally within the cable passageway and so that at least a portion of the snare loop can be selectively extended from the distal tube end by sliding the flexible cable distally within the cable passageway, and a steering tether having a proximal tether end and a distal tether end, the distal tether end being attached to the snare loop. The method comprises inserting the distal end of the flexible tube and the snare loop into the body cavity through a cannula while retaining the proximal tether end outside the body cavity. The method further comprises maneuvering the distal end of the flexible tube through the body cavity until the snare loop is positioned adjacent the object. The method still further comprises placing the steering tether in tension by pulling on the proximal tether end and applying a tensile force to the steering tether sufficient to cause the snare loop to deform in an efficacious manner to facilitate positioning of the snare loop around at least a portion of the object. The method still further comprises maneuvering the snare loop to encircle at least a portion of the object.
Other objects and advantages of the invention will be apparent to one of ordinary skill in the art upon reviewing the detailed description of the invention.